biggest tire that can fit in minitubbed a-body?

moved the wells to the frame, rear is all stock size and placement.
as for the 12" I had them so I tried it and they sit perfect on the rims.Dont remember back space but it was on the big side.
the only thing i needed to trim was the very lower front section of the 1/4 ,about a 1/2 at the bottom up about 3" and at that point to zero. You could not ever tell unless you looked for it.
Tire 315/60R15
Section Width: 12.40 in
Overall Diameter: 29.88 in
Sidewall Height: 7.44 in
Radius: 14.94 in
Circumference: 93.87
Fits real nice,have about 3/4 on both sides
I'll get some pics this weekend

Rumblefish has some rear shots of my car,I'll get him to post up one